Thermally inkjettable acrylic dielectric ink formulation and process

ABSTRACT

An aqueous composition for forming a micro-fluid jet printable dielectric film layer, methods for forming dielectric film layers, and dielectric film layers formed by the method. The aqueous composition includes from about 5 to about 20 percent by 65 weight of a polymeric binder emulsion, from about 10 to about 30 percent by weight of a humectant, from about 0 to about 3 percent by weight of a surfactant, and an aqueous carrier fluid. The aqueous composition has a viscosity ranging from about 2 to about 6 centipoise at a temperature of about 23° C.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/886,126 filed May 28, 2020, which is a continuation of continuationof U.S. patent application Ser. No. 16/138,497 filed Sep. 21, 2018, nowU.S. Pat. No. 10,703,922, which is a continuation of U.S. patentapplication Ser. No. 15/199,829 filed Jun. 30, 2016, now U.S. Pat. No.10,113,074, which is a continuation of U.S. patent application Ser. No.14/152,577 filed Jan. 10, 2014, which is a divisional of U.S. patentapplication Ser. No. 11/839,671 filed Aug. 16, 2007, now U.S. Pat. No.8,659,158, which claims the benefit of U.S. Provisional Application Ser.No. 60/822,532 filed Aug. 16, 2006, entitled “THERMALLY INKJETTABLEACRYLIC DIELECTRIC INK FORMULATION AND PROCESS,” the contents of whichare incorporated herein by reference in their entirety.

BACKGROUND AND SUMMARY

Micro-electronic circuits are typically made using expensive deposition,plating and etching technologies. Such technologies typically requiresignificant investments, and clean room atmospheres. It is often timeconsuming and expensive to make slight variations in components,accordingly, manufacturing lines are often set up for a singleapplication. Additionally, many electronic devices may requiremulti-level wiring or conductors as well as multi-level active andpassive devices. In such multi-level constructions, dielectric layersmay be used between the overlapping layers of active and passivedevices. Accurate placement and formation of the dielectric layers usingconventional techniques is often time consuming and requires specializedequipment. As circuits become more complicated, and require more levelsof devices, there continues to be a need for improved and economicalmanufacturing techniques.

The foregoing and other needs may be provided by aqueous compositionsfor forming micro-fluid jet printable dielectric film layers, methodsfor forming dielectric film layers, and dielectric film layers formed bythese methods. The aqueous compositions include from about 5 to about 20percent by weight of a polymeric binder, from about 5 to about 30percent by weight of a humectant, from about 0 to about 5 percent byweight of a surfactant, and an aqueous carrier fluid. The aqueouscompositions have a viscosity ranging from about 2 to about 6 centipoiseat a temperature of about 23° C.

In another aspect, the disclosure relates to a method of forming adielectric layer. The method includes micro-fluid jet printing onto asubstrate an aqueous film forming composition having from about 5 toabout 20 percent by weight of a dispersion of a polymeric binder, fromabout 10 to about 30 percent by weight of a humectant, from about 0 toabout 3 percent by weight of a surfactant, and an aqueous carrier fluidto provide a dielectric film layer. The composition has a viscosityranging from about 2 to about 6 centipoise at a temperature of about 23°C. The dielectric film layer is provided by curing the micro-fluid jetprinted film forming composition on the substrate.

The embodiments described herein provide improved compositions andtechniques for forming dielectric layers that may be thermal jet printedonto a substrate. Advantage of the compositions and methods disclosedherein are that the compositions have enhanced film forming propertiesand dielectric layers formed with the compositions have improvedelectrical and mechanical properties.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages of exemplary embodiments disclosed herein may becomeapparent by reference to the detailed description of exemplaryembodiments when considered in conjunction with the drawing, as follows;

FIG. 1 is a graphical representation of dielectric constants versusfrequencies for dielectric films made using compositions according tothe disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In order to provide a dielectric layer on a substrate using amicro-fluid jet printing device, fluids for providing the dielectriclayer have certain criteria. Likewise, the resulting dielectric layershave requirements that are important to providing suitable dielectriclayers on a substrate. Such requirements include, but are not limitedto, electrical requirements, e.g., dielectric constant, resistivity,breakdown voltage, dissipation factor; fluid requirements, e.g., jettingreliability, stability, cartridge material compatibility, and the like;film integrity requirements; process/environmental requirements, e.g.,compatibility with subsequent processing environment; andmechanical/physical/chemical requirements. For example, micro-fluidjettable fluids should be stable dispersions of particles or solidshaving a particle size ranging from about 50 to about 500 nanometers, aviscosity ranging from about 1 to about 10 centipoise at 25° C., and asurface tension ranging from about 20 to about 55 dynes per centimeter.Dielectric layers must be uniform and thick enough to provide electricalisolation between conductor layers. Preferably, dielectric layers willbe no thicker than necessary to attain said isolation, but will be thickenough to avoid substantially all defects such as pinholes and cracks.Cured dielectric films should contain substantially no residualhumectant. Another desirable characteristic of the resulting dielectriclayers is that the layers are able to be cured at a temperature belowthe deformation and degradation temperatures of the substrate and anyother functional layers such as conductors or fluid compositionreceiving layers. Film formation and curing may be conducted by airdrying, or by application of heat and/or radiation. The most suitablefilm formation method will vary with the specifies of the formulation,but all heat and energy application must stay within the thermal budgetof the substrate, functional layers, and the device or system to befabricated. The faster the layer are cured and the lower thetemperature, the more desirable. Resulting dielectric layers must notdegrade during subsequent processing steps such as the overprinting andsintering of a conductor layer. The anticipated thermal budget will varydepending on the type and number of layers to be overprinted and cured,but a suitable target for use in a wide variety of systems is nosubstantial degradation at a temperature of about 180° C. after about 2hours, as indicated by low weight loss measured with thermogravimetricanalysis (TGA). Because water will affect the conductivity anddielectric properties of a dielectric film, if is desirable that waterabsorption be as low as possible. Water absorptions have beencharacterized after 24 hour immersion at room temperature conditions,and after 72 hour immersion at 40° C. and should be less than about 5weight percent.

A fluid jet printable formulation that suitably provides a film formingdielectric layer that may meet the foregoing requirements includes adispersion of polymeric binder emulsion, a humectant, and an aqueouscarrier fluid. An optional component of the formulation is one or moresurfactants. Other additives may be included in minor amounts to improvejetting performance and to achieve desirable final film properties.

Aqueous carrier fluids such as water are particularly preferred carrierfluids for the components of the fluid formulation. However, othercarrier fluids, including, but not limited to glycols (e.g., mono-, di-or tri-ethylene glycols or higher ethylene glycols, propylene glycol,1,4-butanediol or ethers of such glycols, thiodiglycol), glycerol andethers and esters thereof, polyglycerol, mono-, di-, andtri-ethanolamine, propanolamine, N,N-dimethylformamide,dimethylsulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone,1,3-dimethylimidazolidone, methanol, ethanol, isopropanol, n-propanol,diacetone alcohol, acetone, methyl ethyl ketone, propylene carbonate,and combinations thereof may be used.

Of the foregoing components of the formulation, an important componentis the dispersed polymeric binder emulsion. Suitable polymeric binderemulsions may be made with acrylic materials, epoxy materials, shellacmaterials, and isocyanate materials. Of the foregoing, the acrylicmaterials are particularly suitable for providing stable fluids that aremicro-fluid jet printable. Acrylic materials, as described herein, mayprovide suitable adhesion to a wide variety of substrates; desirableelectrical properties at room temperature and at moderately elevatedtemperatures; resistance to water, alcohol, alkalis, and acids; highresistance to mineral oil, vegetable oils, greases, and chemical fumes;relatively low water absorption, i.e., less than 0.2 percent in 24hours; superior flexibility; and solderability.

The acrylic materials are typically provided as an emulsion such as anemulsion of a butyl acrylate/methyl methacrylate polymer having aparticles size ranging from about 50 to about 500 nanometers. The fluidjet printable compositions made with the fluid may have a polymerparticles content ranging from about 5 to about 20 percent by weight.For the purposes of this disclosure, particle size refers to the numberaverage particle size and is measured using an instrument that usestransmission electron microscopy or scanning electron microscopy.Another method to measure particle size is dynamic light scattering,which measures weight average particle size. One example of such aninstrument found to be suitable is available from MicroTrac, Inc. ofMontgomeryville, Pa. under the trade designation of Microtrac UPA 150.

Acrylic materials are selected for their ability to form a film duringthe printing process. Accordingly, the acrylic materials may have aglass transition temperature that provides coalescence for filmformation when heated to a temperature ranging from about 80° to about100° C. over a period of time of less than about 5 minutes. For example,suitable film formation may be achieved with acrylic polymers havingglass transition temperatures ranging from about 50° to about 110° C.Acrylic polymers with relatively lower glass transitions may tend toform films at undesirable locations such as on the cartridge nozzleplate or within the nozzle holes thereby preventing jetting.Additionally, films with similar chemistries and relatively higher glasstransition temperatures will tend to have better dimensional stabilitiesin subsequent use and processing environments than those with lowerglass transition temperatures.

Humectants are included in the formulation to prevent the fluids fromdrying or forming films on micro-fluid jetting device nozzle plates.However, if the resulting printed layer contains residual humectant, theglass transition temperature of the layer may be lower than desirable,the layer may have an undesirably high dielectric constant, the layermay be tacky, and/or there may be an oily or slick residue on thesurface of the printed layer or at an interface between the printedlayer and the substrate. Accordingly, the humectant is selected for anability to remain in the fluid at room temperature over an extendedperiod of time, but is readily removed from the fluid as the printedlayer is cured.

Suitable humectants may be selected from dipropylene glycol (DPG),tripropylene glycol (TPG), triethylene glycol (TEG), tetraethyleneglycol, 1-(2-hydroxyethyl)-2-pyrrolidone, trimethylpropane,1,2-propanediol 1,3-propanediol, 1,5-pentanediol, 2-pyrrolidone,polyethylene glycol (PEG), diethylene glycol (DEG), 2,2-thiodiethanol,and mixtures thereof. Humectants with boiling points (BP) that are toohigh such as DPG (BP=232° C.) may not leave a film during the curingprocess resulting in very high water uptake values and weight loss inwater immersion testing. Additionally such relatively high BP humectantsmay provide a slick residue that inhibits overprinting with furtherfluid receiving and conductive layers. Accordingly, a humectant having aBP ranging from about 100° to about 200° C., such as propylene glycol(B.P.=187° C.) may be a more desirable choice because it readily mixeswith water and other ingredients in the fluid formulation and forms a“solution” with much lower co-boiling point. A film layer may be formedwhen an ink composition containing a polymer dispersion and a humectanthaving a BP in the above range is cured.

The amount of humectant used in the fluid formulation should be aminimum quantity needed to provide good start-up qualities and desirablefluid jettability. Accordingly, the humectant may be present in theformulation in an amount ranging from about 10 to about 30 percent byweight.

An optional component that may be used in the fluid formulation is oneor more surfactants. Surfactants may be used to modify the surfacetension and/or viscosity of the fluid to provide fluids having thesurface tension and viscosity described above in order to adjust thejettability characteristics and the wetting characteristics of the fluidon the substrate. The minimal amount of surfactants necessary forreliable jetting should be used because these molecules may remain inthe cured printed film thereby lowering its glass transitiontemperature, raising the dielectric constant, and potentially causingfilm tackiness/drying difficulties, and the like. Accordingly, theamount of total surfactant in the fluid compositions may range fromabout 0 to about 5 wt. %.

Surfactants that may be used to modify the surface tension and viscosityin an aqueous fluid formulation may include, but are not limited to,alkylaryl polyether alcohol nonionic surfactants, such asoctylphenoxy-polyethoxyethanol available from Dow Chemical Company ofMidland, Mich. under the TRITON X series of trade names; alkylamineethoxylates nonionic surfactants such as from Dow Chemical Company underthe TRITON FW series, TRITON CF-10, TERGITOL trade names; ethoxylatedacetylenic diol surfactants available from Air Products and Chemicals,Inc. of Allentown, Pa. under the SURFYNOL trade name; polysorbateproducts available from ICI Chemicals & Polymers Ltd. of Middlesborough,UK under the trade name TWEEN; polyalkylene and polyalkylene modifiedsurfactants available from Crompton OSI Specialties of Greenwich, Conn.,under the trade name SILWET, polydimethylsiloxane copolymers andsurfactants available from Crompton OSI Specialties under the trade nameCOATOSIL; alcohol alkoxylates nonionic surfactants available fromUniqema of New Castle, Del., under the trade names RENEX, BRU, andUKANIL; sorbitan ester products available from Omya Peralta GmbH ofHamburg, Germany under the trade names SPAN and ARLACEL; alkoxylatedesters/polyethylene glycol surfactants available from ICI Chemicals &Polymers Ltd. under the trade names TWEEN, ATLAS, MYRJ and CIRRASOL;alkyl phosphoric acid ester surfactant products such as amyl acidphosphate available from Chemron Corporation of Paso Robles, Calif.,under the trade name CHEMPHOS TR-421; alkyl amine oxides available fromChemmron Corporation under the CHEMOXIDE series of surfactants; anionicsarcosinate surfactants available from Hampshire Chemical Corporation ofNashua, N.H. under the HAMPOSYL series of surfactants; glycerol estersor polyglycol ester nonionic surfactants available from Calgene ChemicalInc. of Skokie, Ill. under the HODAG series of surfactants, availablefrom Henkel-Nopco A/S of Drammen, Norway under the trade name ALPHENATE,available from Hoechst AG of Frankfurt, Germany under the trade nameSOLEGAL W, and available from Auschem SpA of Milan, Italy under thetrade name EMULTEX; polyethylene glycol ether surfactants available fromTakemoto Oil and Fact Co. Ltd, of Japan under the trade name NEWKALGEN;modified poly-dimethyl-silicone surfactants available from BYK Chemie ofWesel, Germany under the BYK 300 series of surfactants; and othercommercially available surfactants known to those skilled in the art.Particularly desirable surfactants are non-ionic surfactants.

Other additives can be included in the fluid compositions in smallpercentages as needed to improve jetting performance, or final filmproperties. Examples of other additives which may be used include, butare not limited to, particulate suspensions used to tailor thedielectric constant of the film layer, such as TiO₂, barium titanate, orstrontium titanate, or particulate suspensions to precipitate/settle andassist with uniformity of solids deposition in the dielectric film layersuch as cerium oxide. When particulate suspensions such as cerium oxideare used, the amount of particulates used in the compositions describedherein may range from about 0 to about 5 weight percent of the totalweight of the composition.

Suitable particles with high dielectric constants that may be used toincrease the dielectric constant of the fluid compositions includestrontium titanate, lead zirconate or other fillers that have a highdielectric constant such as those disclosed in U.S. Pat. No. 6,159,611(Lee) and U.S. Pat. No. 6,586,791 (Lee). Specific examples includeBaTiO₃, SrTiO₃, Mg₂TiO₄, Bi₂(TiO₃)₃, PbTiO₃, NiTiO₃, CaTiO₃, ZnTiO₃,Zn₂TiO₄, BaSnO₃, Bi(SnO₃)₃, CaSnO₃, PbSnO₃, PbMgNbO₃, MgSnO₃, SrSnO₃,ZnSnO₃, BaZrO₃, CaZrO₃, PbZrO₃, MgZnO₃, SrZrO₃, and ZnZrO₃. Densepolycrystalline ceramics such as barium titanate and lead zirconate areparticularly suitable particles. Other particularly suitable particlesinclude metal oxides such as aluminum, zinc, titanium, and zirconiumoxides.

Typically, when particles are included in a micro-fluid jet printablecomposition, the composition may include from about 0 tip to andincluding 15 percent by volume inorganic particles or more, based on thetotal volume of the carrier fluid and inorganic particles.

The inorganic particles may be nano-sized particles having a diameterranging from about 0.5 nanometers to about 3 microns. In someembodiments, the inorganic particles have an average size of 1 to 500nanometers, while in other embodiments the inorganic particles have anaverage size of 10 to 250 nanometers, while in yet other embodiments theparticles have an average size of 20 to 80 nanometers, or from 10 to 30nanometers.

The particles may be mixed, dispersed, suspended, slurried, oremulsified in the carrier fluid. Dispersing agents that may be used tomix, disperse, suspend, slurry or emulsify the particles in the aqueouscarrier fluid may include, but is not limited to, common aqueous-baseddye/pigment dispersants such as lignin sulfonates, fatty alcoholpolyglycol ethers, and aromatic sulfonic acids, for example naphthalenesulfonic acids. Some useful dispersants are polymeric acids or baseswhich act as electrolytes in aqueous solution in the presence of theproper counterions. Such polyelectrolytes provide electrostatic as wellas steric stabilization of dispersed particles in an emulsion. Examplesof polyacids include polysaccharides such as polyalginic acid and sodiumcarboxymethyl cellulose; polyacrylates such as polyacrylic acid,styrene-acrylate copolymers; polysulfonates such as polyvinylsulfonicacid, styrene-sulfonate copolymers; polyphosphates such aspolymetaphosphoric acid; polydibasic acids (or hydrolyzed anhydrides),such as styrene-maleic acid, copolymers; polytribasic acids such asacrylic acid-maleic acid copolymers. Examples of polybases includepolyamines such as polyvinylamine, polyethyleneimine,poly(4-vinylpyridine); polyquaternary ammonium salts such aspoly(4-vinyl-N-dodecyl pyridinium). Amphoteric polyelectrolytes may beobtained by the copolymerization of suitable acidic and basic monomers,for instance, methacrylic acid and vinyl pyridine.

An example of a micro-fluid jet printable fluid composition as describedherein is provided in the following table.

TABLE 1 Component Weight % Range Example Acrylic polymer binder  5-2015.0 Propylene glycol humectant 10-30 15.0 Ethoxylated2,4,7,9-tetramethyl-5-decyn- 0-3 2.5 4,7-diol surfactant Silicon-freealcohol alkoxylate nonionic 0.3 0.8 surfactant Other additives  0-10 0D.I. Water Balance 66.7 Total 100 100

Fluid cartridges were filled with about 20 ml of the dielectric fluidcomposition of the example provided in the above table using a syringeand the cartridges were primed using a vacuum pump followed by wetwipe/dry. A dielectric layer composition was printed on a rigidsubstrate using printer firmware and driver that allowed printing withcontrol of ink drop density.

Printer and software settings were selected to print each layer with720K dots per square inch with a droplet mass estimated to be about 24ng. Optimal dielectric layer coverage will vary depending on theparticular printhead/printer platform and the associated average dropmass. If was important that each layer included sufficient fluid so thatdroplets coalesced to achieve complete coverage with each layer so as tofacilitate uniform film formation with substantially no pinholes orelectrical short pathways.

Layers were sequentially printed and then heated/cured until a totallayer thickness of 20-25 μm was provided. Accordingly, each printedlayer was exposed to a heat lamp to bring the layer temperature to about80° to about 100° C. in about 30 seconds to about 1 minute. Suchtemperature enabled the acrylic polymer particles in the ink to be abovetheir glass transition temperature which allowed for coalescing and filmformation as the humectants and water were evaporated from the layer.The heating step was conducted with a 150 watt halogen flood light at100 mm for 60 seconds or a 250 watt IR heat lamp at 45 mm for 30seconds. Printing and curing were repeated until the total dielectricthickness exceeded 20 um. For example, formulations as provided by theexample in the above table took from about 4 to about 10 layers at 720Kdots/sq·inch with an approximately 24 ng drop mass to provide thedesired thickness. Lower binder loadings may take more layers to achievethe desired thickness. Also, thinner films are frequently prone topinholes and shorts while such problems are minimized with films havingthicknesses above about 20 μm. Once the desired dielectric layer wasprinted and cured, the layer was subjected to a final cure cycle in anoven as follows: ramped at 2.5° C./min from 85° C., to 12° C.; held for30 minutes at 125° C.; ramped down at 5° C./min until the layer reacheda temperature of less than 85° C., then the printed substrate wasremoved from the oven.

Changes to the fluid jet printing process may make it possible tofurther optimize the printing and curing process. For example, printingmore material per layer (for example doubling the layer coverage to 1.44million dots/square inch) may require fewer layers to achieve thedesired thickness. However, printing increased droplets per square inchmay affect water management providing potential solids migrationproblems during the evaporation process resulting in non-uniformthickness layers, i.e., a “coffee ring” effect. For the foregoingformulation, printhead, and substrate, printing 720K dots/square inchallowed for effective water/humectant removal between layers. Heatingmay be achieved using an in-line heater or energy source or a heaton-demand on-carrier heater or energy source incorporated in the printeradjacent to the micro-fluid ejection head instead of using the heatlamps referenced above, thereby simplifying the process for the user andeliminating the need to remove and replace the substrate in the printerbetween subsequent printing and curing of the layers.

It is important that each subsequent layer be heated to above its glasstransition temperature with enough energy to allow the film to coalesce.Temperatures are also desirably high enough to remove the humectantsduring this cure cycle, if film formation and humectant removal arejudged sufficient after the interlayer cure process, then a final curemay not be necessary.

Electrical test structures (e.g., capacitors) were fabricated byprinting over printed silver electrodes on an epoxy FR4 circuit boardcontaining an ink receiving layer or on glossy photographic paper usingthe process described above. Free standing films were fabricated byprinting onto cellulose acetate substrates and then peeling theresulting films. The test structures and films were used to measureelectrical properties, water uptake, and mechanical properties. Theepoxy FR4 grade circuit board is a fire rated electrical-grade laminatemade from woven glass impregnated with epoxy resin. In the designation“FR4,” the F stand for “flame,” the R stands for “retardancies,” and the4 means a #4 epoxy. In general, these substrates have glass transitiontemperatures in the range of from about 125° to about 165° C.

Dielectric constants over a range of frequencies for films made with thecomposition of the example in the above table and printed by theforegoing procedure are illustrated in FIG. 1 . The characteristic curvein FIG. 1 is typical of the performance of a wide variety of acrylicpolymer emulsions. The average dielectric constants at 1 MHz for theexample of Table 1 printed on the glossy photographic paper was 3.44 andon FR4 was 4.12. Other properties for a dielectric layer made with acomposition of Table 1 are contained in Table 2.

TABLE 2 Film from Composition Properties of Table 1 ElectricalProperties Average 4.12^(b)/3.44^(a) dielectric constant K at 1 MHzAverage 0.05^(b)/0.34^(a) Dissipation Factor D at 1 MHz Breakdown >500V/mil^(a) voltage Resistivity >1.0E+14^(a) ohm-cm MechanicalProperties^(c) Tensile strength 3300 (psi) to yield % Elongation to 5.6break Tensile 133000 Modulus (psi) Thermal Properties^(c) 2 hour/180° C.18.7 wt. % weight loss (bulk) Average glass 43.8 transition temperature° C. (TGA Scan) Water Uptake^(c) Properties 72 hour at 40° 6.9 wt. % C.wt. % water uptake 24 hour ambient 2.9 wt. % wt. % water uptake Notes:^(a)Samples prepared on microporous inkjet photo paper ^(b)Samplesprepared on FR4 board ^(c)All samples for measurement of tensile,thermal, and water uptake properties were free standing films.

Good quality films having the required dielectric constant, breakdownvoltage, and resistivity, as well as water uptake, that are suitable foruse in use in a variety of electronic applications may also be achievedwith other acrylic polymer emulsions. In addition to the propertiesstated above, mechanical properties were also acceptable and adhesion tothe underlying ink receiving layer and silver electrode werequalitatively very good.

Finally dielectric films printed in accordance with the disclosedembodiments were shown to function as sealing layers that preventelectromigration of silver between adjacent conductive traces. Todemonstrate this property, conductive silver traces were printedadjacent to one another with a 400 μm gap between them. They were placedin a chamber at 85° C. at 85% relative humidity with a 20V bias betweenthem. When printed on a fluid composition receiving layer on FR4 or onmicroporous photo paper dendritic growth was obvious and electricalshorts occurred in less than 24 hours.

When printed on the dielectric layer made with the composition describedherein and then overprinted with the same dielectric layer such that thesilver traces were encapsulated, no signs of electromigration wereevident after 40 days of continuous electrical bias in the chamber at85° C. and 85% relative humidity.

As a further example of the utility and functionality of the dielectricmade with the composition described herein, a dielectric layer of theexample formulation from table 1 above was fabricated using the aboveoutlined printing and curing steps as part of a multilayer inkjetprinted circuit on an FR4 substrate. The circuit consisted of a firstfluid composition receiving layer, a first conductive layer, thedielectric layer, a second fluid composition receiving layer, and asecond conductive layer. The circuit layout included an electrical viabetween the first and second conductive layers. The circuit alsoincluded surface mount components. When appropriately connected to apower source two surface mount LED's were made to flash in analternating fashion to demonstrate circuit functionality. The dielectriclayer achieved the isolation between conductive layers necessary forproper circuit function.

In summary, functional dielectric films may be fabricated using theabove dielectric ink formulations and micro-fluid jet fabricationprocesses described herein. Such films may have good electrical andmechanical properties which enable their use in a multilayer (2conductive layers on ink receiving layers with a via connection througha dielectric layer) micro-fluid jet printed circuit board.

Another advantage of using micro-fluid ejection heads to deposit thedielectric films on a substrate is that such printing techniques enabledielectric layers to be precisely deposited without potentially damagingor contaminating the substrate. Micro-fluid jet printing is anon-contact printing method, thus allowing insulating or dielectricmaterials to be printed directly onto substrates without damaging and/orcontaminating the substrate surface due to contact, as may occur whenusing screens or tools and/or wet processing during conventionalpatterning, depositing, and etching. Micro-fluid jet printing alsoprovides a highly controllable deposition method that may provideprecise and consistently applied material to the substrate. Micro-fluidejection heads for depositing the fluids described above may be selectedfrom ejection heads having thermal actuators, piezoelectric actuators,electromagnetic actuators, and the like.

Devices and articles that may be made using the fluid compositionsaccording to the disclosure include transistors, diodes, capacitors(e.g., embedded capacitors), and resistors. The foregoing components maybe used in various arrays to form amplifiers, receivers, transmitters,inverters, oscillators, electroluminescent displays and the like.

It is contemplated, and will be apparent to those skilled in the artfrom the preceding description and the accompanying drawings thatmodifications and/or changes may be made in the embodiments of thedisclosure. Accordingly, it is expressly intended that the foregoingdescription and the accompanying drawings are illustrative of exemplaryembodiments only, not limiting thereto, and that the true spirit andscope of the present disclosure be determined by reference to theappended claims.

1. An aqueous composition comprising: from about 5 to about 20 percentby weight of a dispersion of a polymeric binder; from about 5 to about30 percent by weight of a humectant; from about 0.3 to about 3 percentby weight of a surfactant; and an aqueous carrier fluid, wherein thedielectric layer has an average dielectric constant at 1 MHz of 3.44 to4.12, wherein the aqueous composition further comprises one or moreadditives that include at least BaTiO3, SrTiO3, Mg2TiO4, Bi2(TiO3)3,PbTiO3, NiTiO3, CaTiO3, ZnTiO3, Zn2TiO4, BaSnO3, Bi(SnO3)3, CaSnO3,PhSnO3, PbMgNbO3, MgSnO3, SrSnO3, ZnSnO3, BaZrO3, CaZrO3, PhZrO3,MgZnO3, SrZrO3, or ZnZrO3.
 2. The aqueous composition of claim 1,wherein the humectant comprises propylene glycol.
 3. The aqueouscomposition of claim 1, wherein the humectant has a boiling point belowabout 200° C.
 4. The aqueous composition of claim 1, wherein thesurfactant comprises at least one non-ionic surfactant.
 5. The aqueouscomposition of claim 1, wherein the aqueous composition has a surfacetension ranging from about 25 dynes/cm to about 55 dynes/cm.
 6. Theaqueous composition of claim 1, further comprising metal oxide particlesdispersed in the aqueous composition.
 7. The aqueous composition ofclaim 1, wherein the aqueous composition further comprises one or moreadditives selected from the group consisting of: TiO₂ and cerium oxide.8. The aqueous composition of claim 1, wherein the aqueous compositionfurther comprises one or more additives, wherein the additives arealuminum metal oxide, zinc metal oxide, titanium metal oxide orzirconium metal oxide.
 9. The aqueous composition of claim 1, whereinthe polymeric binder has a glass transition temperature of 50° C. to100° C.
 10. The aqueous composition of claim 1, wherein the aqueouscomposition has a viscosity ranging from about 2 to about 6 centipoise.11. A method of reducing silver migration between adjacent silver layersof a micro-electronic circuit comprising: forming a dielectric layer,the step of forming a dielectric layer comprising: micro-fluid jetprinting onto a substrate an aqueous film forming compositioncomprising: from about 5 to about 20 percent by weight of a dispersionof a polymeric binder emulsion; from about 10 to about 30 percent byweight of a humectant; from about 0 to about 3 percent by weight of asurfactant; and an aqueous carrier fluid to provide a dielectric filmlayer, wherein the aqueous composition has a viscosity ranging fromabout 2 to about 6 centipoise at a temperature of about 23° C.; andcuring the dielectric film layer on the substrate to provide thedielectric layer; and disposing the dielectric layer between theadjacent silver layers.
 12. The method of claim 11, wherein the filmlayer made with the aqueous composition has a glass transitiontemperature ranging from about 40° to about 110° C.
 13. The method ofclaim 11, wherein the humectant comprises a compound selected from thegroup consisting of dipropylene glycol, tripropylene glycol, triethyleneglycol, tetraethylene glycol, 1-(2-hydroxyethyl)-2-pyrrolidone,trimethyolpropane, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol,2-pyrrolidone, polyethylene glycol, diethylene glycol, triethyleneglycol, tetraethylene glycol, 2,2-thiodiethanol, and mixtures thereof.14. The method of claim 11, wherein the surfactant comprises at leastone non-ionic surfactant.
 15. The method of claim 11, wherein thepolymeric binder emulsion is selected from the group consisting ofpolyacrylate binder emulsions, epoxy binder emulsions, shellac binderemulsions, and isocyanate binder emulsions.
 16. The method of claim 11,wherein the dielectric film layer is cured with heat to raise thetemperature of the film layer to above a glass transition temperatureand below a decomposition temperature for the film layer.
 17. The methodof claim 11, wherein the substrate comprises a fluid compositionreceiving layer onto which the film forming composition is printed. 18.The method of claim 11, wherein the micro-fluid jet printing and curingsteps were repeated from about 2 to about 20 times to provide thedielectric layer, further comprising curing the dielectric layer with afinal cure step.